Zeolite-Promoted Platinum Catalyst for Efficient Reduction of Nitrogen Oxides With Hydrogen

Internal combustion engine fueled by carbon-free hydrogen (H2-ICE) offers a promising alternative for sustainable transportation. Herein, we report a facile and universal strategy through the physical mixing of Pt catalyst with zeolites to significantly improve the catalytic performance in the selective catalytic reduction of nitrogen oxides (NOx) with H2 (H2-SCR), a process aiming at NOx removal from H2-ICE. Via the physical mixing of Pt/TiO2 with Y zeolite (Pt/TiO2 + Y), a remarkable enhancement of NOx reduction activity and N2 selectivity was simultaneously achieved. The incorporation of Y zeolite effectively captured the in-situ generated water, fostering a water-rich environment surrounding the Pt active sites. This environment weakened the NO adsorption while concurrently promoting the H2 activation, leading to the strikingly elevated H2-SCR activity and N2 selectivity on Pt/TiO2 + Y catalyst. This study provides a unique, easy and sustainable physical mixing approach to achieve proficient heterogeneous catalysis for environmental applications

Profile of immunoglobulin G N-glycome in COVID-19 patients: A case-control study

Coronavirus disease 2019 (COVID-19) remains a major health challenge globally. Previous studies have suggested that changes in the glycosylation of IgG are closely associated with the severity of COVID-19. This study aimed to compare the profiles of IgG N-glycome between COVID-19 patients and healthy controls. A case-control study was conducted, in which 104 COVID-19 patients and 104 age- and sex-matched healthy individuals were recruited. Serum IgG N-glycome composition was analyzed by hydrophilic interaction liquid chromatography with the ultra-high-performance liquid chromatography (HILIC-UPLC) approach. COVID-19 patients have a decreased level of IgG fucosylation, which upregulates antibody-dependent cell cytotoxicity (ADCC) in acute immune responses. In severe cases, a low level of IgG sialylation contributes to the ADCC-regulated enhancement of inflammatory cytokines. The decreases in sialylation and galactosylation play a role in COVID-19 pathogenesis via the activation of the lectin-initiated alternative complement pathway. IgG N-glycosylation underlines the complex clinical phenotypes of SARS-CoV-2 infection

Regulation of MntH by a Dual Mn(II)- and Fe(II)-Dependent Transcriptional Repressor (DR2539) in Deinococcus radiodurans

The high intracellular Mn/Fe ratio observed within the bacteria Deinococcus radiodurans may contribute to its remarkable resistance to environmental stresses. We isolated DR2539, a novel regulator of intracellular Mn/Fe homeostasis in D. radiodurans. Electrophoretic gel mobility shift assays (EMSAs) revealed that DR2539 binds specifically to the promoter of the manganese acquisition transporter (MntH) gene, and that DR0865, the only Fur homologue in D. radiodurans, cannot bind to the promoter of mntH, but it can bind to the promoter of another manganese acquisition transporter, MntABC. β-galactosidase expression analysis indicated that DR2539 acts as a manganese- and iron-dependent transcriptional repressor. Further sequence alignment analysis revealed that DR2539 has evolved some special characteristics. Site-directed mutagenesis suggested that His98 plays an important role in the activities of DR2539, and further protein-DNA binding activity assays showed that the activity of H98Y mutants decreased dramatically relative to wild type DR2539. Our study suggests that D. radiodurans has evolved a very efficient manganese regulation mechanism that involves its high intracellular Mn/Fe ratio and permits resistance to extreme conditions

A Novel OxyR Sensor and Regulator of Hydrogen Peroxide Stress with One Cysteine Residue in Deinococcus radiodurans

In bacteria, OxyR is a peroxide sensor and transcription regulator, which can sense the presence of reactive oxygen species and induce antioxidant system. When the cells are exposed to H2O2, OxyR protein is activated via the formation of a disulfide bond between the two conserved cysteine residues (C199 and C208). In Deinococcus radiodurans, a previously unreported special characteristic of DrOxyR (DR0615) is found with only one conserved cysteine. dr0615 gene mutant is hypersensitive to H2O2, but only a little to ionizing radiation. Site-directed mutagenesis and subsequent in vivo functional analyses revealed that the conserved cysteine (C210) is necessary for sensing H2O2, but its mutation did not alter the binding characteristics of OxyR on DNA. Under oxidant stress, DrOxyR is oxidized to sulfenic acid form, which can be reduced by reducing reagents. In addition, quantitative real-time PCR and global transcription profile results showed that OxyR is not only a transcriptional activator (e.g., katE, drb0125), but also a transcriptional repressor (e.g., dps, mntH). Because OxyR regulates Mn and Fe ion transporter genes, Mn/Fe ion ratio is changed in dr0615 mutant, suggesting that the genes involved in Mn/Fe ion homeostasis, and the genes involved in antioxidant mechanism are highly cooperative under extremely oxidant stress. In conclusion, these findings expand the OxyR family, which could be divided into two classes: typical 2-Cys OxyR and 1-Cys OxyR

Surveying the Down syndrome mouse model resource identifies critical regions responsible for chronic otitis media

Chronic otitis media (OM) is common in Down syndrome (DS), but underlying aetiology is unclear. We analysed the entire available mouse resource of partial trisomy models of DS looking for histological evidence of chronic middle-ear inflammation. We found a highly penetrant OM in the Dp(16)1Yey mouse, which carries a complete trisomy of MMU16. No OM was found in the Dp(17)1Yey mouse or the Dp(10)1Yey mouse, suggesting disease loci are located only on MMU16. The Ts1Cje, Ts1RhR, Ts2Yah, and Ts65Dn trisomies and the transchomosomic Tc1 mouse did not develop OM. On the basis of these findings, we propose a two-locus model for chronic middle-ear inflammation in DS, based upon epistasis of the regions of HSA21 not in trisomy in the Tc1 mouse. We also conclude that environmental factors likely play an important role in disease onset

Research on Catastrophic Pillar Instability in Room and Pillar Gypsum Mining

Gypsum mines in China are mostly exploited through room and pillar mining. Due to backward mining technology and a long history of mining, a great number of pillars were left in gypsum mines. Many serious work safety accidents occurred as the result of goaf instability in history, which posed severe threats to the security of people’s lives and property. Based on the characteristics of surrounding rock damage, this research improved the constitutive equation of gypsum rock mass damage by establishing a damage evolution model and introducing a shape parameter. Meanwhile, the cusp catastrophe equation was deduced based on the catastrophe theory and the constitutive equation of gypsum rock mass damage, thus summarizing the criteria for pillar instability; the pillar safety factor was obtained by means of the interrelation between pillar load and pillar strength. Based on the criteria for pillar instability and the pillar safety factor obtained, the necessary and sufficient conditions for pillar stability were concluded. These conclusions are of significance in that they provide theoretic reference for the treatment of gypsum goaf, as well as for further mining

TiN层微观结构对CVD TiC-TiCN-TiN多层涂层耐磨性能的影响

TiN layers with diverse microstructures were deposited on TiC-TiCN layer by chemical vapor deposition through changing the volume ratio of N_2/H_2.The effect of microstructure of TiN layer on friction property of TiC-TiCN-TiN multilayer coating was investigated,and multilayer coating products from domestic and foreign company were also comparatively analyzed in terms of microstructure,hardness and wear resistance.Results showed that the highest hardness and the lowest friction coefficient of TiC-TiCN-TiN multilayer coating can be obtained at a N_2/ H_2 ratio of 1.5∶1,along with a wear resistance superior to the coatings made by foreign companies.The hardness and the anti-friction performance of the oxide layer formed during friction process have crucial effects on wear resistance of the multilayer coating

Enhanced Thermoelectric Performance of c-Axis-Oriented Epitaxial Ba-Doped BiCuSeO Thin Films

Abstract We reported the epitaxial growth of c-axis-oriented Bi1−x Ba x CuSeO (0 ≤ x ≤ 10%) thin films and investigated the effect of Ba doping on the structure, valence state of elements, and thermoelectric properties of the films. X-ray photoelectron spectroscopy analysis reveal that Bi3+ is partially reduced to the lower valence state after Ba doping, while Cu and Se ions still exist as + 1 and − 2 valence state, respectively. As the Ba doping content increases, both resistivity and Seebeck coefficient decrease because of the increased hole carrier concentration. A large power factor, as high as 1.24 mWm−1 K−2 at 673 K, has been achieved in the 7.5% Ba-doped BiCuSeO thin film, which is 1.5 times higher than those reported for the corresponding bulk samples. Considering that the nanoscale-thick Ba-doped films should have a very low thermal conductivity, high ZT can be expected in the films

Modal Computation and Analysis Based on Phase Sequence of LLC Resonant DC-DC Converter

LLC resonant DC-DC converter has wide working range, good voltage gains, and soft switching performance. So it is widely used in power transformation systems of new energy equipment such as UPS, electric vehicle, and photovoltaics (PV). The conduction loss in the main circuit constitutes the main loss occurred in the LLC resonant converter. It may greatly improve the power conversion efficiency of the converter by reducing the conduction loss. To solve the above problems, a method is proposed to calculate and design the parameters of the resonant element in this paper. This method abandons the traditional time sequence mathematical model, and, in order to reduce the effective value of the main loop current of resonant converter, the phase sequence modal analysis is applied. With ZVS as the constraint condition, the design parameters of resonance element that can minimize the conduction loss can be obtained. In the final part, an experimental prototype (300W) is designed and the effectiveness of the mentioned method is verified